1. Field of Invention
The present invention relates to a light guide plate and a backlight module. More particularly, the present invention relates to a light guide plate having a V-cut structure and a backlight module containing the light guide plate.
2. Description of Related Art
A backlight module is one of the key components for a liquid crystal display (LCD) panel. Since liquid crystals themselves do not emit light, the backlight module is required for providing a light source, whereby the LCD panel can show a normal image of uniform brightness. The backlight module generally comprises a light source and a light guide plate and several optical films disposed above the light guide plate, such as a diffuser and a brightness enhancement film (BEF) etc., wherein the light guide plate is used to lead the light emitted by the light source to the optical films, and then the optical films are used to redistribute the light in more directions so that the light emitted can be distributed more uniformly.
Since a light guide plate with microstructures has a more concentrated light pattern than a flat light guide plate, conventional skills often implement the microstructures on the light guide plate to promote the lightness of the light guide plate. A conventional light guide plate with microstructures has an incident surface, an emitting surface and a reflecting surface, and the reflecting surface has the V-cut microstructures of the same type, wherein each of the V-cut microstructures has a main angle. The convention skill generally adjusts the depth or pitch of the V-cut microstructure to control light emitting amount, thereby satisfying the requirement of light uniformity. However, when light is transmitted within the conventional light guide plate with microstructures, a front light beam just entering the light guide plate will form an end light beam after being transmitted, and the light pattern of the end light beam will be different from that of the front light beam, thus causing light pattern variations to occur on the front, middle and end zones of the light guide plate, i.e. the light incident angles from the respective zones to an optical film has quite a lot of variations. On the other hand, since the optical film above the light guide plate is formed from uniform material, the light incident angles to the optical film are required to be as close as possible. Therefore, the light emitting patterns of the conventional light guide plate can hardly generate consistent light incident angles on the front, middle and end zones of the light guide plate, and thus the requirements of optimum light incident angles to the optical film cannot be satisfied.